Open-source enterprise instant messaging
Version: 0.1.5messenJer is an instant messenging server and client written in Java. It is targeted towards small to medium size enterprises and offers a number of features that those markets are looking for in an instant messenger.
Operating System: Mac OS X
messenJer has the capability of logging everything, all messages, thus reducing a corporation's liability over the employee's use of the enterprise's IM solution.
It's simple, running in Java and using MySQL (or possibly any other database) as a back end. messenJer runs everywhere, because it's Java.